Description and Operation
A three circuit cooling system is used on this engine. In addition to the conventional thermostat for the small and large coolant circuit, a further thermostat for controlling a mini coolant circuit is used.
The mini coolant circuit means that the coolant only flows through the exhaust side of the cylinder head during the first stage of the warm-up phase. From here the coolant arrives at the oil cooler via the heat exchanger and from there it is passed to the coolant pump. In this phase there is no coolant flow in the cylinder block nor on the intake side of the cylinder head.
This leads to rapid warm-up of the engine and the engine oil, through which the friction at the lubrication points is reduced at an early stage.
Furthermore, in addition to the usual mechanical coolant pump, an electric coolant pump is installed in the coolant circuit.